1. Field of the Invention
This invention relates in general to switching regulators and more specifically to a switching regulator with input current limiting capabilities.
2. Description of the Related Art
Some electronic equipment require regulated power supply voltages for efficient and/or safe operation. Switching regulators are used to provide a regulated DC voltage and to adjust the voltage level from a DC power source such as a battery or an AC powered rectifier with filtering. A switching regulator generates a signal having a duty cycle to a control terminal of a power switch for controlling the voltage level of the regulated output voltage.
Some power sources may have limits on the amount of current that can be drawn from a power source. For example, for systems that charge a battery from a Universal Serial Bus (USB) connector, the amount of current drawn may be limited to a particular maximum level, e.g. 100 mA, 500 mA, or 950 mA at ±5%. Also, it may be desirable to limit the amount of current drawn by the regulator to prevent damage to the regulator.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The Figures are not necessarily drawn to scale.